Halogenated aromatic polyesters, such as the condensation product of 4,4'-isopropylidene-2,2',6,6'-tetrachlorodiphenol or 4,4'-isopropylidene-2,2',6,6'-tetrabromodiphenol with isophthalic acid and/or terephthalic acid or the ester forming derivatives thereof, have been used to produce a number of inherently non-burning fibrous materials which are particularly advantageous when fibrous articles are required for use in fire-control environments, such as children's sleepware, suits for fire fighters, hospital furnishings, and uniforms for military and civilian personnel.
These polyesters are frequently used in combination with an oxide of antimony, i.e., either antimony trioxide or antimony pentoxide, to form a flame retardant fiber composition. However, when such antimony oxides are mixed with the halogenated aromatic polyesters, the antimony oxide containing polyester composition becomes difficult to spin because of clogging of the holes of the spinneret.
When "Nyacol" antimony pentoxide, a very small particle size (15-50 millimicrons) colloidal antimony pentoxide produced by Nyacol Inc., is employed in the polyester composition, there is substantially no clogging problem. However, this particular colloidal antimony pentoxide contains an Ethomeen dispersion stabilizer. This stabilizer is a polyethoxylated aliphatic amine which will decompose the halogenated aromatic polyester when it is hot drawn. As presently known, there is no such colloidal antimony pentoxide which can be prepared without a dispersion stabilizer which will decompose the halogenated aromatic polyester when it is hot drawn.
The search has continued for improved processes for spinning compositions of an oxide of antimony and halogenated aromatic polyester. This invention was made as a result of that search.